The diagram shows part of a factor tree for 168: 168 splits into two branches, 8 and a box marked with a question mark. The branch showing 8 splits further into three boxes: 2, 2 and 2. The box marked with a question mark splits into two boxes: 3 and 7. Work out the number in the box marked with a question mark, and use it to write 168 as a product of its prime factors.
Figure (to be drawn): A factor tree with 168 at the top. 168 branches down to two boxes: 8 (left) and a box marked with a question mark (right). The 8 box branches down to three boxes: 2, 2 and 2. The question-mark box branches down to two boxes: 3 and 7.
(Total for Question 12 is 2 marks)